1. Field of the Invention
The invention relates to slide fasteners and particularly to chains for slide fasteners gapped by having sections of the interlocking fastening elements removed, as well as to methods and apparatus for manufacturing such chains.
2. Description of the Prior Art
The prior art, as exemplified in U.S. Pat. Nos. 2,619,148; 3,001,904; 3,340,594; 3,488,239; 3,510,379; 3,577,292; 3,639,969; 3,748,709; 3,770,552; 3,804,577; and 3,884,738, contains many slide fasteners having chains wherein portions of the rows of slide fastening elements have been removed to form gaps in the chains. Some slide fastener chains are gapped by severing the fastening elements into pieces and removing the pieces from the edges of the tapes and other chains are gapped by pulling the fastening elements from the edges of the tapes; care must be taken in the removal of the fastening elements so that the threads on the inner edge portions of the tapes are not cut to thus avoid unraveling of the carrier tapes supporting the rows of fastening elements. The above U.S. Pat. Nos. 3,001,904; 3,340,594; 3,488,239; and 3,510,379 disclose the reinforcement of the ends of textile stringer tapes by welding thermoplastic foils on or in the tapes. The above U.S. Pat. Nos. 3,577,292; 3,639,969; 3,748,709; 3,770,552; 3,804,577; and 3,884,738 disclose the utilization of ultrasonic energy to fuse articles together including the fusion of fastening elements together at one end of a slide fastener and to cut articles, such as cutting the tapes of a slide fastener chain.